Thermionic device for wireless telegraphy and telephony



April 29, 1924. 1,492,000

H. J. ROUND THERMIONIC DEVICE FOR WIRELESS TELEGRAPHY AND TELEPHONY Filed Aug. 26, 1920 m MMM Patented Apr. 29, 1924.

UNITED Y STA TES PATENroFFicE;

HENRY JOSEPH ROUND, 0F LONDON, ENGLAND, ASSIGNOB 'DO RAJJIO- CORPORATION 0F AMERICA, OF NEW YORK. N. Y.. A CORPORATION OF DELAWARE.

THEBMIONIO DEVICE FOR WIRELESS TELEGBAVPHY AND TELEPHONY. 3

Application led August 26, 1920. Serial No. 406,181.

To all 'whom 'it may concern.'

Be it known that LHENRYJSEPH ROUND, a subject of the King of Great Britain, and resident of 9 Woodberry Crescent, Muswell Hill, London, England, vhave invented new and useful Improvements in Thermionic Devices for Wireless Telegraphy and Te-y lephony (for which I have filed an application in England dated August 7, 1919), of which the following isa specification.

This invention relates to improvements in thermionic devices for wireless telegraphy and telephony and has for its object the production of a valve having a low resistance.

It is well known that in thermionic devices of the Fleming valve type the space current flowing is equal to KV where V represents the anode volts applied and K is a function of the mechanical dimensions of the valve. With a cylindrical anode and an axial filament K varies directly as the length (Z) of the cylinder and inversely as its radius 0r y l .1 cVnl c= v(1) where' w isv the radius or distance between the anode and cathode. If the anode and cathode are parallel surfaces K varies directly as the area of the surfaces and inversely `as the square of the distance between them or l akigrl (2) great distance from the filament, while around this anode and as near. to it as possible I arrange a second anode. l" then make the rst anode positive by applying to it sufficient Voltage to bring up to it enough electrons for the required purpose, and I treat this first anode as though it were itself the actual source of the electrons and the potential were applied `between it and the second anode. f -O A third electrode or control member ref erably also of grid form can be intro uced in order to give electric control and to furnish a low resistance valve' having high magnifying properties.

My invention is illustrated by the accompanying diagrams, in which;

Fig. 1 is a diagrammatic view illustrating the invention. l

Fig. 2 is a section through a valve constructed according to my invention.

Fig. 3 shows another form in which the two Vgrids and the anode are flat.

Fig. 4 shows another form of valve. FFigt. 5 is a section on the line A--A of ig. 6 is a detail View of the supporting member used in the form shown in Fig. 4.

Fig. 7 is a diagram showing an arrangement of circuits utilizing a valve.

In Figure 1, G and A represent respectively a grid-like anode and'anode at distances 0' and r-I-m from a filament F, be-

ing the distance between G and A. Then if sufficient voltage is applied between Gr and F, G being made positive, G can be considered asa new source of electrons, and the current between G and A as given in (2) will be crVnZ/, whereas if A had been a cylinder at distance m from the filament the current as given in (1) would have been kVnZ/m. Therefore for the same value of V the ratio of these currents is 7' that is to say, by making a" large and m small the resistance of the valve is reduced.

Now the distance of a cylinder from a filament must usually be larger than is desirable because of the difficulty introduced by the expansion of the filament, whereas two cold electrodes can be mechanically anchored very near together, so that the distance may be made very small.

In Figure 2, F is a straight stretched filament, G is a prismatir` grid-like anode.

stretched upon four supports S of steatite, glass` metal or other suitable material, and A is an anode surrounding thewhole. Between the grid like anode and the outer ,anode is a control grid g stretched on supports s which are of steatite or other insulating material In Fig. 3 the grid like anode G and the grid gend the anode AA are in the form of flat plates separated by fiat insulating inembers s, S. l j

In the t'orm of valves shown in Figs. 4, 5 and 6 the. grid like anode G is formed of a number of turns of wire wrapped round two Opposite faces S of a stcatite former having the general shape of a parallelepiped. The other faces 8,8, are wider than the faces S and the grid g is formed of a number of turns of wire wrapped round these faces s so that the wires constitutingthe grid like anode G are separated by a small distance on both sides from the"wires constituting the grid g. In the middle of the grids is a filament F supported by leading-in wires f at one corner of the former and by a wire f at the opposite corner. The anode c onsists of two square plates A, one at each side, supported from pins a on the former.

Figure 5 is a diagram showing lthe arrangement of the circuits, when such a valve is t'o be used for amplifying. The incoming oscillations are led into the oscillatory circuit O connected to the grid g and the lilament. fB is a battery by which the grid like anode'G can be made positive. The anodefilament circuit contains a battery 7) and an oscillatory circuit o the currents in which can be caused to influence a detector in any ordinary way.

What I claim is 1. In a thermionic device the combination of a cathode, an anode situated at a distance from the said cathode, a second anode situated on that side of the first anode which is remote from the cathode, the distance between the first anode and the second anode being small as compared with the distance between the first anode and the cathode and means for applying a positive potential to the first anode.

2. Ina thermionic device the combination of a cathode, an anode situated at a vdistance from said cathode, a second anode situated on that side of the tirst anode which is remote from the cathode, the distance between the lfirst anode and the second anode being small as compared with the distance between the iirst anode and the cathode, a control grid situated between the irst anode and the second anode and means for applying a positive potential to the lirst anode.

3. In a thermionic device the combination of a. cathode, an anode surrounding saidl cathode, a second anode surrounding the first anode, the distance between the first anode and the second anode being small as compared with the distance between the first anode and the cathode and means for applycompared with the distance between the first anode.A and the cathode",4 a control grid situated between the first anode and4 the.

sei-ond anode and means for applying a positive potential to the irst. anode.

5. Ina therinionic device the combination of a heated lilaincntary cathode. a cold anode situated ata dist alice from the heated cathode, a second anode situated on that side ofthe cold cathode which is remote from the heated cathode, the distance bet veen the cold anode and the second anode being small as compared with .the distance between the cold anode and the heated cathode, means for applying a positive potential to the cold anode, and means for applying a greater positive potential to the second anode.

6. In a thermionic device a combination of heated filamentary cathode, a cold anode situated at a distance from the heated cathode, a second 4anode situated on that side of the cold anode which is remote from the heated cathode, the distance between the cold anode and the second anode being small compared with ,the distance between the cold anode and the heated cathode, a control grid situated between the cold anode and the second anode, means for applying a positive potential to the cold anode, and means for applying a greater positive potential to the second anode.

7. In a thermionic device the combination of a heated cathode, a grid-like anode spaced from theheated cathode, a second anode adjacent the grid-like anode, the distance between the grid-like anode and the second anode being small compared with the distance between the grid-like anode and the' heated cathode and means for applying positive potential to the grid-like anode.

8L In' a thermionic. device the combination of a heated cathode, a grid-like anode spaced from the heated cathode, a second anode adjacent the gridlike anode. the distance between the grid-like anode and the second anode being small compared with the distance between the grid-like anode and the heated cathode, a control grid situated between the grid-like anode andthe second anode yand means for applying a positive potential to the grid-like anode.

9. In radio receiving apparatus the combination with a thermionic device having a heated filamentary cathode, a cold anode situated at, a distance from the heated cathode,`a second anode situated on that side of the cold anodewhich is remote from the heated cathode, the distance between the cold anode and the second anode being small compared with the distance between the cold anode and the heated cathode and a control grid situated between the cold anode and the second anode of means for applying a positive potential to the cold .anode and means for applying a signalling potential sol between the heated ilamentary cathode and the control grid.'

10. In radio receiving apparatus the combination with a therinionic device having a heated cathode, a grid-like anode spaced from the heated cathode, a second anode adacent to the grid-likeanode, the distance between the grid-like anode and the second anode being small compared with the distance between the grid-like anode and the 

